Dental pit and fissure sealants may be applied by any one of several types of applicators, such as brushes, sponges, cotton plegets with tweezers, dispensers with disposable tips made of plastic tubing, and the like. Each type applicator offers certain advantages depending upon the nature of the sealant being applied, and the dexterity of the operator.
Most dental pit and fissure sealants are liquids of varying viscosities. Some are polymerized by radiation from an ultraviolet light source while others are designed to be polymerized by high intensity visible light. Still others are polymerizable or set by means of a redox reaction between an organic peroxide and a reducing agent, commonly benzoyl peroxide with dimethyl-p-toluidine, and other tertiary amine derivaties of toluidine.
Application of the sealant by means of a brush is not entirely satisfactory. Only a small amount of the sealant is carried by the brush resulting in a time-consuming procedure with concomitant fatigue to the operator. Further, brushing the sealant onto surfaces of posterior teeth uniformly is difficult, and even skilled technicians accidentally misapply the sealant to soft tissue where it may cause irritation.
Plastic sponges and cotton plegets suffer from several disadvantages. Both are picked from a small box with tweezers. Very frequently, the sponges will cling together due to static electrical charges thereon. Similarly, intermingled fibrils of the cotton plegets will cause undesirable clinging. Both the plastic sponges and cotton plegets soak up large quantities of the sealant which tend to adhere quite tenaciously to the sponges and plegets. Cotton plegets frequently leave linters embedded in the sealant on the tooth surfaces where they often act as wicks to thus contribute to clinical failure. After each application, the sponge or pleget must be removed by hand from the tip of the tweezers. In multiple applications of sealant in the mass treatment of school children, for example, sealant accumulates on the tweezers to further add to the frustrations of the operator.
Sealants may also be applied by means of a dispenser. A small tube or tip of plastic is inserted into the dispenser head. A lever, mounted behind the head of the dispenser, is depressed to actuate a rubber diaphragm for expelling a small amount of air therewithin. Releasing the lever while the end of the dispensing tip is immersed in the sealant urges some into the tip where it may then be applied to the oral cavity by again depressing the lever. Such dispensing devices are not entirely satisfactory. For example, the head of many prior art dispensers is relatively bulky, and when placed inside an oral cavity, often obstructs clear vision of the dentition, especially in the smaller cavities of children. Also contributing to obstructed vision is the clinical operator's own hand which depresses the lever.
Further, the disposable plastic tip is seated in the head of the dispenser rather loosely. Consequently, it is often difficult to avoid the flow of sealant into the rubber diaphragm, and particularly where the end of the plastic tip is directed upwardly, as when sealant is applied to maxillary dentition. After the sealant is applied, the plastic tip must be manually removed from the dispenser, subjecting the operator to contact with the sealant necessitating time-consuming and annoying removals thereof.
The present invention substantially overcomes the deficiencies of prior art applicators or dispensers and permits a precise amount of sealant to be applied to dentition of the maxilla or mandible. After the sealant has been applied, the tip is instantaneously ejected upon the mere application of slightly excessive pressure to a plunger member which, under normal operating thumb pressures, will urge the sealant from the dispenser onto the dentition surfaces. The ability of the present dispensing device to thus eject the disposable tip without manually unscrewing or physically separating it from the dispenser is an important feature of the invention contributing to its safe, aseptic, and convenient usage.
The present dispenser may be used to apply sealant to a single tooth surface, estimated to require between about 2 to 6 mg; or to an entire quadrant, since the dispenser is capable of carrying more than 50 mg of the sealant. The combined length of the tip with approximately one-half the syringe body makes it convenient for the operator to apply the sealant to posterior teeth without visual obstruction by the head of the dispenser or by the operator's hand. The handle is comfortably held and can be rotated to any desirable position.